The automotive industry has been trying for years to develop lower volatile organic content (VOC) coatings without sacrificing performance in areas such as durability, gloss retention, solvent and humidity resistance and the like.
The present invention produces a low VOC coating composition which is particularly well-suited for use as an automotive enamel coating or as a coating for industrial applications. This invention relates to lower VOC, non-aqueous dispersions (NAD's) comprising an acrylic polymer stabilized in an alkyd steric stabilizer. The NAD's of this invention are particularly useful in automotive applications as one and two component primers, sealers and topcoat enamels and in industrial applications as coatings for equipment, parts and the like.
For purposes of this invention, NAD's are polymeric particles having a core-shell type morphology dispersed in a non-polar solvent such as a hydrocarbon. The "core" is comprised of a polar copolymer produced by a free-radical addition reaction and the "shell" comprises an alkyd resin or an acrylic/alkyd copolymer. A large portion of the shell resin is soluble in the hydrocarbon solvent and thus forms the continuous phase. However, a small portion of the shell resin is adsorbed onto the surface of the core polymer particles and acts as a steric stabilizer for those dispersed particles.